Solving laundry at UC Berkeley

Submitted by admin on Mon, 06/06/2011 - 13:57

Nearly
a million people have watched UC Berkeley's PR2 folding towels and
sorting socks on YouTube, and it's easy to understand why: having a
robot that can do your laundry is a fantasy that's been around since The Jetsons,
and while we're not there yet, it's not nearly as far off a future as
it was before the PR2 Beta Program. Since those demos, one of the
research groups at Berkeley has been working on ways of making the
laundry cycle faster, more efficient, and more complete, and for
starters, they've taught their PR2 to reliably handle your pants.

The goal of Pieter Abbeel’s group is to teach a robot to solve the laundry
problem. That is, to develop a system to enable a robot to go into a
home it's never seen before, load and unload a washer and dryer, and
then fold the clean clothes and put them away just like you would. The
first aspect of this problem that the group tackled was folding, which
is one of those things that seems trivial to us but is very difficult
for a robot to figure out since clothes are floppy, unpredictable, and
often decorated with tasteless and complicated colors and patterns.

Last year, the Berkeley PR2 (unofficially named Brett, for “Berkeley Robot
for the Elimination of Tedious Tasks”) showed us that it could pick a
towel out of a pile of clean laundry one by one and neatly fold and
stack them, which was an impressive demo. Somewhat less impressive was
the fact that the robot would take between 20 and 25 minutes to neatly
fold one single towel, which, let's face it, isn't entirely practical.
That time has now been cut down to under six minutes, with the potential
for as little as two minutes per towel if they really crank the robot
up.

The way that Berkeley has been able to improve the performance of the
folding software so dramatically is by reducing the dependence on a
complex vision system and instead relying on gravity and the properties
of cloth. The PR2 now just picks up a towel wherever is convenient and
then drags it across a folding table, knowing that as it does, the piece
of the towel furthest away from the gripping point must necessarily be a
corner. By grabbing that corner and repeating the procedure, the robot
is able to quickly pick up two opposite corners of the towel. This puts
the towel into one of two states, and from there, the PR2 has no trouble
folding it. This general approach also works on shirts and pants and
whatever else a robot might find in your laundry.

While
the actual folding is what we care about most, the trickiest part for
the robot is just getting a random piece of crumpled up laundry into a
state where it can tell what kind of clothing it’s got, and that’s what
grad student Arjun Singh has been working on. Specifically, he’s taught
the PR2 to unfold
and identify complex items of clothing like shirts, skirts, and pants.
This is an essential capability for the PR2, since it enables the robot
to grab a whole bunch of random laundry out of the dryer, uncrumple and
identify each piece, reorient its grip, and then fold it properly.

At
this stage, the laundry problem as a whole is “almost in principle
solved,” as student Stephen Miller explains. “There are tiny little
things that keep us from being able to put all the pieces together
reliably, but the detection problem and the folding and unfolding, all
of that is pretty much a non-issue regardless of what article of
clothing you’re looking at.” Other students are working on getting the
PR2 familiar with how to work a washing machine, how to unload a dryer,
and even how to put clothes on hangers. Plus, all of Berkeley’s
experience with deformable objects has led to some clever ROS packages
that could also be adapted to (say) teach a robot to make your bed every
morning.

Professor
Pieter Abbeel is optimistic that by the time the PR2 Beta Program ends
in 2012, they’ll be able to do an entire laundry cycle from start to
finish. This of course means that at some point early next year, you’ll
start seeing a lot of computer science students dragging bags of dirty
laundry into the Berkeley robot lab, and going home with stacks of clean
clothes, neatly folded and smelling of robot.